Molecular imprinting is a known technique for making synthetic hosts which are the man-made mimics of biological receptors or enzymes that possess sites for molecular recognition and catalysis. Molecular imprinting involves creating template-shaped cavities in polymer matrices with the memory of the template molecules used for molecular recognition. This system is based on the “lock and key” model which is the system used by enzymes for substrate recognition. Enzymes have active binding sites with a unique geometric structure which selectively bind to a substrate having a corresponding shape.
In prior art molecular imprinting processes, substrate-selective recognition sites are prepared in a matrix using a casting procedure with a template molecule. Functional monomers attach to, or assemble around, a template molecule and the functional monomers and the template molecule are subsequently linked together by a cross-linking agent to form a molecularly imprinted polymer network. Removal of the template molecule from the molecularly imprinted polymer network creates a structure complementary to the template structure allowing its tight and selective uptake.
Despite the broad use of the above described molecular imprinting technique, there are inherent limitations with this process that decrease its practical suitability. For example, one inherent limitation is the inability for polymers to generate molecule size cavities with structure details due to the non-structure orientation around the templates and the macro-scale nature of the prior art molecular imprinting process. It is difficult to use a polymer as a building matrix to make molecule size recognition hosts. Another limitation is that the molecular recognition for sensor application is separated from transduction. For example, in nature, where there are ion channels in membranes, it is hard to distinguish molecular recognition from transduction, the two main components of sensors, as they are integrated and not separable. Other limitations and problems with the prior art molecular imprinting technique described above include heterogeneity in binding affinities, slow mass transfer in and out of the polymer matrix or network, overall low binding affinity, lack of a read-out for complexation, and slow template leaching.
Accordingly, there is a need for molecular recognition matrix that overcomes these limitations and problems and, in particular a need for a molecular recognition matrix that provides molecular recognition cavities with antibody-like ability to bind and discriminate between molecules or other structures.